docs/pages/Learning ___ Azure ___ AZ-900%3A Microsoft Azure Fundamentals ___ Cloud Concepts.md

Introduction to cloud computing

- Define cloud computing.
	- Compute Power
	- Storage
	- Pay only ressources you use
	- Upkeep is done by cloud provider
- Describe the shared responsibility model.
	- Cloud Provider: Physical security, power, cooling, and network connectivity are the responsibility
	- Consumer: responsible for the data and information stored in the cloud.
	- IAAS (Infrastructure)-> PAAS (Platform) -> SAAS (Software)
	- ![Diagram showing the responsibilities of the shared responsibility model.](https://learn.microsoft.com/en-us/training/wwl-azure/describe-cloud-compute/media/shared-responsibility-b3829bfe.svg){:height 231, :width 700}
- Define cloud models, including public, private, and hybrid.
	- | **Public cloud** | **Private cloud** | **Hybrid cloud** |
	  | ---- | ---- | ---- |
	  | No capital expenditures to scale up | Organizations have complete control over resources and security | Provides the most flexibility |
	  | Applications can be quickly provisioned and deprovisioned | Data is not collocated with other organizations’ data | Organizations determine where to run their applications |
	  | Organizations pay only for what they use | Hardware must be purchased for startup and maintenance | Organizations control security, compliance, or legal requirements |
	  | Organizations don’t have complete control over resources and security | Organizations are responsible for hardware maintenance and updates |  |
	- Azure ARC
		- Manage Cloud environment
- Identify appropriate use cases for each cloud model.
- Describe the consumption-based model.
	- Capital expenditure (**CapEx**)
		- upfront one time expenditure
	- Operational expenditure (**OpEx**)
		- spending money on services or products over time
		- Cloud computing is here
- Compare cloud pricing models.
	- pay-as-you-go pricing model
- ## Describe the benefits of using cloud services
	- Describe the benefits of high availability and scalability in the cloud.
		- **uptime** (or availability)
		- **demand** (or scale)
			- Scalability refers to the ability to adjust resources to meet demand
			- **vertical**
				- increasing or decreasing the capabilities of resources (i.e. RAM or CPU)
			- **horizontal**
				- adding or subtracting the number of resources (i.e. VMs or containers)
		- each Service has own SLA
	- Describe the benefits of reliability and predictability in the cloud.
		- **Reliability** is the ability of a system to recover from failures and continue to function
			- decentralized design and global scale across data centers
		- **Predictability**
			- **performance** predictability
				- Autoscaling, load balancing, and high availability
			- **cost** predictability
				- track cost in real time
				- Total Cost of Ownership (TCO) or Pricing Calculator
	- Describe the benefits of **security** and **governance** in the cloud.
		- Set templates
		- update all your deployed resources to new standards
		- Cloud-based auditing
		- handle distributed denial of service (DDoS)
	- Describe the benefits of **manageability** in the cloud.
		- Automatically scale resource
		- Deploy resources based on (preconfigured) templates
		- Monitor health and replace failing resources
		- Automatic alerts
		- Use
			- Web Portal, CLI, APIs, PowerShell
- ###Describe cloud service types
	- Describe Infrastructure as a Service (IaaS).
		- renting the hardware in a cloud datacenter (i.e. Hetzner)
		- **Scenarios**
			- Lift-and-shift migration
			- Test an development
	- Describe Platform as a Service (PaaS).
		- maintain the operating systems, databases, and development tools
		- **Scenarios**
			- Development framework
			- Analytics or business intelligence
	- Describe Software as a Service (SaaS).
		- Use Maintained Software
		- **Scenarios**
			- Email and messaging.
			- Business productivity applications.
			- Finance and expense tracking.
	- Identify appropriate use cases for each cloud service (IaaS, PaaS, SaaS).